IRC SP 119-2018 serves as an extensive guide offering methodologies for planting and landscape design along urban roadways in India. It covers aspects such as plant selection, tree pit creation, street furniture, irrigation techniques, and upkeep procedures to enrich the environment of city roads. This code is vital for professionals like civil engineers, landscape designers, and urban planners focusing on sustainable urban greenery and streetscape enhancement.
Overview
IRC SP 119-2018 serves as an extensive guide offering methodologies for planting and landscape design along urban roadways in India. It covers aspects such as plant selection, tree pit creation, street furniture, irrigation techniques, and upkeep procedures to enrich the environment of city roads. This code is vital for professionals like civil engineers, landscape designers, and urban planners focusing on sustainable urban greenery and streetscape enhancement.
Audience
Contents
Structure
This chapter highlights sustainable landscaping methods integrated with urban roads aimed at reducing air pollution, urban heat effects, flooding, water shortages, and soil erosion. Key features include the use of broad-canopied shade trees and permeable paving to combat heat islands and pollution; incorporation of bio-swales and detention basins for stormwater management; implementation of drip irrigation and recycled water to address water scarcity; maintaining a minimum clearance of 4.5 meters above the roadway for tree protection; and planting guidelines for traffic islands, medians, and plazas with emphasis on high-branched trees and permeable surfaces. Seating provisions are designed to avoid interference with stormwater flow.
This section describes the design methodology encompassing detailed surveys for topography, vegetation, soil, and microclimate. It advocates tailoring planting schemes based on project type and road classification, considering functional zones such as medians and footpaths. Plant selection emphasizes native, drought-tolerant species, appropriate spacing, and integration with bio-swales for runoff management. Functional design principles ensure safety and visibility while harmonizing street furniture and utilities with vegetation.
Focused on practical execution, this chapter covers the integration of landscaping with road functions including erosion control and stormwater management. It details standards for materials and workmanship, street furniture specifications, irrigation systems favoring drip methods, and protection of trees and subgrade. Water treatment plants for sustainable water utilization are also described.
This part outlines a comprehensive maintenance schedule extending up to ten years, involving activities such as site surveys, pit excavation, planting, watering frequency adjustments, weeding, and casualty replacements. It provides best practices for transplantation of mature trees, monitoring survival rates, and parameters to ensure healthy growth. Staking and protection techniques are emphasized to minimize damage during establishment.
This subsection explains how planting design is influenced by the road hierarchy, with local streets emphasizing shade trees for comfort and traffic calming, and collector roads focusing on dust and noise screening along with safety and aesthetics. It specifies clear sight distances according to design speed and pruning clearance requirements to maintain visibility and safety. Slope and drainage management techniques including the use of grass and bio-swales are also highlighted.
Guidelines for planting include aligning trees in straight lines, using shade-providing native species, maintaining clear pedestrian zones through pruning, and avoiding monocultures by mixing species. The document details planting practices for medians of varying widths, footpaths, cycle tracks, and traffic islands, with recommendations on shrub heights, tree canopy spreads, and species selection to ensure safety and visual appeal.
This section provides specifications for irrigation system design to prevent water wastage, including maximum precipitation rates, separation of valves, anti-drain valves, and underground pipe embedding. It advocates drip irrigation and recycled water use, manual control, and soil moisture monitoring. A formula for calculating daily water requirements based on canopy area, evapotranspiration, plant factors, and irrigation efficiency supports efficient water management.
Minimum dimensions for tree pits are specified as 3.3 square meters area, 1.8 meters minimum side length, and 1.2 meters depth. Median widths require a minimum of 1 meter internal dimension and retaining walls of specified thickness to protect road subgrade. Guidelines include soil composition, root ball protection, staking, mulching, and clearance distances from utilities to ensure tree health and infrastructure safety.
This chapter addresses the placement and specifications of street furniture such as benches, bollards, cycle parking, and paving. Furniture is located within the multi-functional zone without obstructing pedestrian or non-motorized transport paths. Dimensions for seating, bollard heights and spacing, and tactile paving requirements for accessibility are discussed to ensure comfort, safety, and usability.
Design criteria for kerbs facilitating stormwater flow into bio-infiltration zones include kerb cut width of 450 mm with chamfered sides, a minimum slope of 2 degrees to guide runoff, and use of gravel mulch to prevent erosion. Different kerb types are described, with side wings to stabilize slopes. Integration with bio-swales and infiltration trenches is emphasized to enhance stormwater management.
To prevent subgrade damage caused by tree roots, the standard recommends planting trees within cylindrical pipes to direct roots downward. Specifications include cast-in-place blocks with grooves for root guidance. Median plantation types vary by width, with detailed shrub and tree height recommendations. Pruning for clear height and avoidance of monocultures or exposed soil are stressed for durability and safety.
Maintenance is divided into phases starting before planting with site preparation and continuing for up to ten years with periodic watering, weeding, casualty replacements, fencing, and fertilization. Detailed schedules specify activities by year and season. Tree transplantation best practices and survival monitoring parameters are included to ensure sustained plant health.
This section describes proper handling of plants during transport and planting to avoid injury, including soil ball handling, protection from wind damage, and immediate planting or watering upon delivery. It details staking methods using three stakes with cotton ties, buried sufficiently for stability, and timely removal. Cluster planting of native, deep-rooted species is recommended for wind protection.
The appendix outlines the composition of the Highways Specifications & Standards Committee and its subcommittees, including members from government departments, academic institutions, and industry experts. The approval process involves draft preparation by subgroups, iterative consultations, committee reviews, executive committee endorsement, and final council approval prior to publication, ensuring thorough vetting and consensus.
Frequently Asked
The standard recommends a minimum tree pit area of 3.3 m², with each side measuring at least 1.8 meters and a depth of 1.2 meters. For medians, the internal width should be at least 1 meter, supported by a retaining structure such as a 230 mm thick brick wall or a 75 mm concrete wall. Soil backfill should include approximately 18% organic compost and 10% clay. If drainage is problematic, a mix of three parts manure, two parts sweet earth, and one part sand is advised. Tree pits should be lined with a toe wall or concrete kerb, about 150 mm wide and 450 mm deep, flush with the footpath, and treated with anti-termite solutions prior to filling. Staking with 2.2-meter treated wooden stakes and root zone aeration using lava slag mixed with soil may be employed to promote healthy root growth.
Erosion control is managed through a combination of natural vegetation and structural measures. Gentle slopes are stabilized using native grasses and shrubs, while steeper inclines may require terracing or retaining walls. Grass swales placed at slope tops and bottoms reduce runoff velocity. Waterlogged areas are treated with aquatic plants, and xerophytic species are used for sandy or desert-like soils. Surface runoff is directed into natural swales or drainage systems to prevent water accumulation and soil erosion.
To prevent risks associated with monocultures, the standard limits any single species to a maximum of 10% of the total planting in a stretch, any genus to 20%, and any family to 30%. No more than 12 consecutive trees of the same species are recommended. The proportion of a species also depends on the total number of trees onsite, with stricter limits as numbers increase. This diversity strategy helps reduce vulnerability to pests, diseases, and environmental stresses.
Recommended street furniture includes benches, dustbins, bollards, cycle parking, and toilet blocks. Benches and dustbins should be placed every 50 meters within the multi-functional zone, with benches typically 450 mm in seat height and 1200 to 1500 mm in length. Bollards serve to separate traffic zones and are specified at heights of 450 mm near resting areas and 750 mm as vehicle barriers, spaced 600 to 1100 mm apart to allow wheelchair access. Toilet blocks are suggested every 300 to 500 meters. All furniture must be located to avoid obstructing pedestrian and non-motorized transport pathways.
Water scarcity is addressed by implementing efficient irrigation methods such as drip irrigation to minimize water use and avoid runoff. The use of recycled water is encouraged, and xeriscaping with drought-tolerant plants reduces irrigation demand. Stormwater from impervious surfaces is harvested and directed to irrigate trees. Irrigation systems should have water meters, separate valves for different emitters, anti-drain valves, and pipes buried 0.3 to 0.6 meters deep. Manual overrides and soil moisture monitoring are recommended to optimize watering schedules and conserve resources.
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